There are estimated to be more than 200,000 different species of flies, midges, gnats, and mosquitos in the world, but only about half of them are known and described. All belong to the order Diptera (Wikipedia article), whose name means “two winged.” The only insect order with more species is the beetles.
There are many species of green bottle flies (Wikipedia) that look very similar. All belong to the family Calliphoridae (Wikipedia), also known as blowflies. That family contains roughly 1,100 species. It is a huge, complex family whose internal relationships are disputed. Some entomologists think there may be several separate lineages in the family, from different origins.
Like many blue or green animal colors in nature, the shiny luster of these flies comes from light diffraction through tiny structures in the surface of their body, not from any kind of pigment. As a result, the color can change depending on the angle of the light. Blue jays, peacocks, and Morpho butterflies also get their blue and green colors from diffraction of light.
Blowflies in general, and green bottles in particular, are incredibly sensitive to the smell of dead flesh. They are often the first insects to arrive when an animal dies. Forensic entomologists can estimate the time of death of an animal or human by looking at the life stages of blowfly maggots and other insect larvae within the body.
The little beauty shown here bopped around the garden for almost an hour while I was photographing all sorts of stuff. I kept finding it basking in the sun. The rock must have been especially warm, because it hung out there for a long time.
How curious and strange, that this beautiful green-gold work of art spent its early life completely surrounded by a dead animal’s rotting body.
Not long after our green friend flew away, a different beauty showed up. This syrphid fly (flower fly / hover fly) was uncharacteristically just sitting there among the Bacopa flowers. Usually they are seen hovering almost in place, or darting from one flower to another.
The family Syrphidae (Wikipedia) has even more species than the Calliphoridae, numbering more than 6,000. Most of the adults eat pollen or drink nectar. The larvae have more varied food – some of them are valuable predators, eating aphids and other small insects found on plants.
Two flies, just hanging out in the sun. Who wants to fly around when you can just soak up some rays on a nice green leaf or rock?